Closes #2141

This PR integrates the `getPrFiles` function into the GitLab's wrapper.

Closes #2085

fix: match current version

Refactors nuget lookups to use generatic logic and fill in repositoryUrl to enable changelogs.

Adds basic support for renovating C# project files. The scope is initially limited to:

- .Csproj only (no VB.NET / F#)
- SDK style csproj's only (this is the default in .net core anyway)
- Limited to nuget.org support (no custom repository support)

Closes #935, Closes #2050

Closes #2101 #2092

Adds a series of functions related to the commenting aspect of GitLab for the API wrapper. These functions are: `getComments`, `addComment`, `editComment`, `deleteComment`, `ensureComment` and `ensureCommentRemoval`. 

This reverts commit 7bc9a2db.

This reverts commit 29d00aa4.